Hibiscus sabdariffa L. EXTRACT

Abstract

Hibiscus sabdariffa is a tropical shrub species cultivated in many countries and is mainly produced for its red calyces that are used for a tea beverage. H. sabdariffa contains compounds that are reported to have antibacterial activities. Therefore, this study aimed at evaluating the antimicrobial effect of H. Sabdariffa on S. typhi. The crude ethanol and aqueous extracts were obtained by maceration. The susceptibilities of S. typhi to aqueous and the ethanolic H. sabdariffa extracts were investigated using Agar well diffusion techniques on Xylose Lysine Deoxycholate (XLD) agar media, the setups also included both the positive (ceftriaxone) and negative (water) controls and were done in triplicates. Broth dilution in nutrient broth of S. typhi was carried out and used to determine the optical densities (ODs) for different concentrations of H. sabdariffa extracts of 0mg/ml, 50mg/ml, 100mg/ml, 300mg/ml, 400mg/ml and the optical densities were used to determine the MIC (minimum inhibition concentration) for both the ethanolic and aqueous extract. S. typhi was sensitive to ceftriaxone (positive control), ethanolic and aqueous H. sabdariffa extracts while water (negative control) had no activity on S. typhi. However, S. typhi was more sensitive to ceftriaxone with a mean zone of inhibition of 43.33mm, followed by ethanolic extract with a mean zone of inhibition of 14.44mm and then aqueous extract with a mean zone of inhibition of 13.76mm and finally water with a mean zone of inhibition of 0.00mm. The data was analysed by one-way ANOVA. H. sabdariffa had a statistically significant antimicrobial activity against S. typhi [ANOVA F (2, 12) = 13.69, P-value=0.0008]. The zones of inhibition of the aqueous extract of H. sabdariffa were statistically significant compared to the ethanolic extract [ANOVA F (2, 13) = 961.0, p- value < 0.0001]. The MIC of the ethanolic extract was significantly less than that of the aqueous extract [ANOVA F (4, 10) = 78.02, p- value, 0.0001]. Therefore H. sabdariffa possesses antimicrobial activity against S. typhi with ethanol extracts having a slightly higher antimicrobial activity than aqueous extract.